They appeared post 7-ish
To me, Kirk Douglas seems more similar to Burt Lancaster than to either Robert Mitchum or Charlton Heston.
Bill Pullman is the one still making movies. Still able to, anyway.
I have confused Ryan Reynolds and Ryan Gosling in movies before. Two generically handsome actors with the same first name. I find it easier to tell them apart by personality than by sight. Even in their acting personas, Reynolds always seems to play a wisecracking smartass while Gosling usually plays more serious roles.
Not to be confused with the Ivy League Chrises:
There’s a persistent rumor that Matthew McConaughey and Woody Harrelson are brothers
And when I saw Skeet Ulrich in As Good As It Gets, I thought I was watching Johnny Depp.
Keira Knightly and Natalie Portman.
And they’re all made out of ticky tacky, and they all look just the same.
The way I remember them, Reynolds was Deadpool, and Gosling was Young Hercules.
The two I always mix up are Elizabeth Banks and Rachel McAdams.
For the older crowd, there was James Franciscus, James Farentino and Tony Franciosa. Even TV guide had a jokey article that they were really all the same person.
I get how the brain can trip over the names but I don’t understand not telling them apart. They look nothing alike.
I don’t quite understand the conflation of Pullman and Paxton. They are both character actors named Bill but I feel their looks are unique enough and their body of work is so distinctive that they shouldn’t be mixed up. I don’t want to disparage anyone else’s experience on this but both have/had roles that has affected me so differently that I can always tell them apart.
Bill Pullman: Spaceballs, Ruthless People, Independance Day, While You Were Sleeping, Torchwood: Miracle Day
Bill Paxton: Fish Heads, Near Dark, Aliens, Navy Seals, True Lies, A Simple Plan, Twister, Big Love
Also I must admit that my teenager’s name is Paxton but we named him that long after I discovered my appreciation for the actor. 
I’ve never understood that one either. Perhaps it’s like Hold me closer Tony Danza. A meme, if you will.
I thought of a couple actors I can never get straight. Not due to looks, they look nothing like each other, but their names.
James Marsters and James Marsden. The first was Spike on Buffy, the other was Cyclops in X-Men. (The X-Men movie which also had Shawn Ashmore who I previously mentioned.) The “James Mars Guys” are two I will never ever stop getting confused. I will always have to Google a name to remember. I had to do it before writing this post.
Neither do the Bills, Chis’, or Ryans. I can see confusing the names but not faces
Their personas are also different: Pullman usually plays goofballs, and Paxton usually played assholes.
Speaking of Paxtons who look nothing like another similarly named actor, I always have to remind myself which one is Sara Paxton and which is Sarah Polley.
I’ve gotten Kerry Washington and Gugu Mbatha Raw confused.
Before Lord of the Rings, I confused Sean Astin and Ethan Hawke.
Lord of the Rings helped me solidify who Sean Astin is.